London's Metropolitan Police force said officers were called just after 9 a.m. Monday to a hotel where a woman in her 40s was found dead. The police force said the death was being treated as "unexplained."

O'Riordan was born on Sept. 6, 1971 in Ballybricken, southwest Ireland. In 1990, she answered an ad from a local band in nearby Limerick city — then called The Cranberry Saw Us — that was looking for a lead singer.

A name change and a confluence of factors turned The Cranberries into international stars. Their guitar-based sound had an alternative-rock edge at a time when grunge was storming the music scene.

The band's songs — on which O'Riordan was chief lyricist and co-songwriter — had a Celtic-infused tunefulness. And in O'Riordan the group had a charismatic lead singer with a distinctively powerful voice.

Heavy play on MTV for their debut single "Dream" and the singles that followed helped bring the group to the attention of a mass audience.

Irish Prime Minister Leo Varadkar tweeted Monday that "for anyone who grew up in Ireland in the 1990s, Dolores O'Riordan was the voice of a generation. As the female lead singer of a hugely successful rock band, she blazed a trail and might just have been Limerick's greatest ever rock star. RIP."

The band released three more studio albums before splitting up in 2003. O'Riordan released a solo album, "Are You Listening," in 2007, and another, "No Baggage," in 2009.

My first time hearing Dolores O'Riordan's voice was unforgettable. It threw into question what a voice could sound like in that context of Rock. I'd never heard somebody use their instrument in that way. Shocked and saddened to hear of her passing, thoughts are with her family.